CBI director-general John Cridland has become increasingly frustrated after months of delays to infrastructure projects. Photograph: Linda Nylind for the Guardian

The boss of Britain's biggest business lobby group has attacked the government for failing to boost the economy after a series of delays to infrastructure projects.

John Cridland, the director general of the CBI, said ministers were in many cases too busy infighting to agree funding for projects that needed government support.

He warned that essential upgrades to roads and funding for renewable energy were being held up while the economy continued to suffer.

"I think it is really disappointing how long it is taking to get momentum and urgency into the growth plan," he said in an interview with the Financial Times.

Worries that the eurozone crisis will continue to drag down UK growth have been fuelled in recent weeks by figures showing that the double-dip recession may prove longer than expected.

"The risks that the eurozone headwinds can really flatten the economy are still pretty considerable," he said.

Cridland has become increasingly frustrated with the coalition government after months of delays to infrastructure projects put forward by industry with civil servant support.

The CBI published its own wish list last year for a series of projects around the country it said would get the wheels of the economy moving and create vital jobs.

He criticised Justine Greening's transport department for stalling on the construction of a possible toll road to unblock the congested A14 route, which carries container traffic to the port of Felixstowe in Suffolk.

"On Justine Greening's desk is an options report from officials following a call for evidence," he said, adding that practical results were need quickly: "I was talking about diggers on the ground."

He said officials seemed "dazzled in the headlights" – a reference to the apparent paralysis he sees in Whitehall ministries covering a range of policy areas.

Green energy initiatives have become a battleground between the chancellor, George Osborne, and energy minister, Ed Davey, over future subsidy levels for renewable energy and wind. Cridland said it was creating uncertainty in a sector which needed to think in the long term.

"It's got stuck in a political row," he said. "The economics of it are blindingly obvious."

The CBI is in favour of a revamped private finance initiative which it expects the Treasury to unveil in the budget next March. Last year Osborne signalled his eagerness to get pension funds and other big investors to back large infrastructure projects. But without a coherent policy in place, institutional investors had proved reluctant.

Cridland said he supports the chancellor's austerity measures, but argued they needed to be matched by a more energetic approach to infrastructure investment.